As an indwelling catheter, the item disclosed in FIGS. 1 to 4 of Japanese Unexamined Patent Publication No. JP-A-2011-115630 (Patent Document 1) is well known as a prior example. This conventional indwelling catheter is equipped with a hollow catheter base, a catheter tube, a flexible hemostasis valve, and a hollow pusher installed to be able to slide inside the catheter base for doing the opening and closing operation of the hemostasis valve, and the hemostasis valve is constituted having a pusher receiving part that encloses and holds the outer circumference of the pusher.
Then, for the operation, by the hemostasis valve having a pusher receiving part that encloses and holds the outer circumference of the pusher, during puncturing (before removal of the inner needle), the inner needle passes through the pusher and the hemostasis valve and is made to face the needle tip from the tip of the catheter tube (state for which puncture is possible), and after puncturing (when the inner needle is removed), the hemostasis valve is resealed (valve closed) so that blood leakage is prevented (hemostatic condition), and also, by connecting a male connector from the back of the catheter base, the pusher passes through the hemostasis valve and is locked at the front position, and the pusher stops at the same position, so even if the male connector is removed, the hemostasis function is not expressed, and a conductive state between the catheter base and the catheter tube is maintained.
However, with the indwelling catheter noted above, when the patient temporarily suspends treatment, and it is necessary to remove the male connector (e.g. when treatment is temporarily suspended due to a physiological phenomenon such as the patient experiencing an urge to urinate or the like), there is the disadvantage of having to temporarily block the catheter using some kind of method.
To eliminate the problem described above, as an indwelling catheter that can be connected a plurality of times, the item disclosed in Japanese Unexamined Patent Publication No. JP-A-2008-173206 (Patent Document 2) is well known as a prior example.
This indwelling catheter is linked to the base of a cannula, and has an outer needle main unit with an empty space part in communication with the inner cavity of the cannula provided on the interior. On the interior of this outer needle main unit, a connector part is provided in a movable state, and a valve body is installed in front of the connector part. This valve body passes through the tip side part of the connector part in liquid tight fashion, making the cannula inner cavity and the connector part flow path be in communication, and is also equipped with an opening and closing hole that is closed when the tip side part of the connector part is not inserted, and blocks the front part side and the back part side of the space part of the outer needle main unit. Furthermore, with this constitution, a valve body presser plate equipped with an insertion hole in which the tip side part of the connector part can be inserted is provided on the back surface side of the valve body, and a coil spring is installed between the valve body presser plate and a spring bearing part formed on the connector part.
Then, for the operation, when treatment is suspended and the male connector connection is temporarily canceled, the connector part is moved to the back by the coil spring provided inside the outer needle (catheter base), the valve body is closed, and blood leakage is prevented.
However, when using a constitution with a coil spring installed inside the catheter base, it is necessary to make the strength of the spring a fixed strength or greater to return the pusher reliably to its original position, and it is necessary that the coil spring have a certain degree of length. As a result, it is necessary to have a catheter base equipped with enough space to provide a coil spring of a sufficient length, and the size of the indwelling catheter becomes large, and a circumstance occurs for which it is difficult to fix to the skin, or for which the indwelling catheter gets in the way during treatment.